112 THE MEDUSAE. 



other with them elongate, narrow, and oval. The series shows clearly that 

 Vanhciffen had good ground for maintaining that the forms, heart-shaped and 

 triangular, are but variations, often caused by contraction and preservation, 

 of a single ground form, and that this difference is not indicative of specific 

 divergence. I have no doubt that L. tetraphjlla of the present collection is 

 identical with the form from the Pacific described by Maas imder the name 

 L. rosacea, and of which he has given an excellent figure ('97, taf. 3, fig. 7), 

 and with those recorded by him (: 05) under the same name from the col- 

 lections of the " Siboga" ; and at the same time there seems to be no stable 

 character to separate it from the specimens of Liriope with triangular 

 gonads from both Atlantic and Indian oceans, which Vanhbffen (: 02'') has 

 united under the name L. tetraphjlla. It is doubtful whether all the 

 species included by Vanhoffen in the " tetraphylla " group, particularly 

 L. cerasus, L. euryhia, and L. hicolor, really belong there, since in the form 

 of the gonads they suggest close affinity with L. scutigera. 



Maas (: 05) distinguishes three varieties in the "Siboga" collection, — 

 L. tetraphylla with ovoid, L. rosacea with triangular, and L. compacta with rhom- 

 boid gonads, but inasmuch as the present series shows all gradations between 

 the two extremes, there is good reason to believe that these represent 

 merely three successive stages in the development of a single species. 



I am puzzled to find any satisfactory identification for the second species 

 contained in the collection, that with narrow oval gonads ; and since an 

 incorrect identification is worse than none, because it may prove misleading 

 to students of the geographic distribution of this troublesome genus, I hesi- 

 tate to assign any specific name to it. 



Liriope tetraphylla Chamisso. 



Geryonia tetraphylla Chamisso, '20, p. 357, taf. 27, fig. 2. 



Liriope tetraphylla Gegenbaur, '56, p. 257; Vanhoffen, : 02^, p. 82; Maas, : 05, p. 61. 



Iiiriantha tetraphylla Haeckel, '79, p. 286. 



Xanthea tetraphylla L. Agassiz, '62, p. 365. 



Liriope crucifera Haeckel, '79, p. 290. 



Geryonia rosacea Eschscholtz, '29, p. 89. 



Liriope rosacea Gegeubaur, '56, p. 257 ; Maas, '97, p. 26, taf. 3, figs. 7, 8; : 05, p. 62, 



taf. 9, figs. 58, 59. 

 Glossocodon lutkenii Haeckel, '79, p. 293, taf. 18, fig. 5. 

 Liriope liitkeni Vanhoffen, : 02'', p. 79. 



Liriope compacta Maas, '93, p. 37, taf. 3, fig. 11 ; : 05, p. 62, taf. 9, figs. 55-57. 

 Glossocodon agaricus Haeckel, '79, p. 293. 

 Liriope agaricus Vanhoffen, : 02'>, p. 79. 



